(1) Field of the Invention
The present invention relates to the field of disk drive storage units. Specifically the present invention relates to the technology of disk drive storage units and their manufacture.
(2) Prior Art
Disk drive storage mediums, or "hard" disk drives, are mechanisms that store digital information on a spinning disk or platter. The magnetic platters are approximately from 1.5 inches in diameter up to 8 inches or more depending on the type of disk drive used or the storage capacity of the drive. Several platters arranged in parallel, one mounted on top of the next, rest in a drive case. Each platter is centrally fixed and carefully aligned in order to provide the spinning action required. A platter has two sides in which information can be stored. Also mounted to the drive case is an actuator arm which holds a read/write head associated with each platter side. If there are eight platters there could be up to 16 heads attached to the actuator arm.
The actuator arm remains fixed with respect to the spinning platters but can move across the diameter of the spinning platter in order to provide access to all of the surface area of the platter as the platter spins and as the actuator arm moves the read/write head across the platter diameter. Since the head remains in a fixed path and the platters spin, data is stored according to the arc of the heads across the platters, this is a circle. Therefore, magnetic data stored on a hard drive platter is stored in circular paths or sectors by the magnetic head passing across the magnetic surface. The rate that this information can be accessed or stored at depends on the rate that the platters can spin. Conventional prior art disk drives can obtain a spin rate of approximately 3600 to 6400 revolutions per minute. The faster the spin rate, the faster information can be supplied by the drive and stored to the disk drive unit. Therefore, it is advantageous to increase the platter spin rate of the drive unit. The read/write heads associated with each platter fly above the platter surface on a cushion of air that is created by the air forces of the spinning platters. The heads ride very closely with the platter surface to they can read and write magnetic information onto the platter surface. The characteristics of the air dictate the size, shape and movement of the flying read/write heads.
The platters and actuator arm with associated heads are contained in a chamber within the disk drive unit. This chamber protects the platters and delicate movement required for the precise alignment of the platters to the actuator arm. Usually this chamber is sealed within a "clean room" having a reduced particle count so as to reduce the amount of dust and other particles that may become trapped within the drive case when the chamber is sealed. These particles could destroy the disk drive if they were to become entrenched into the platters and mechanisms.
In order to achieve the spin rates of conventional disk drives, energy must be supplied to a spindle motor which spins the platters which are coupled to a central spindle. Once the platters speed up to their desired rate, energy must be supplied in order to overcome what is called "viscous drag" forces that act upon the platters. As the platters spin, friction from the surrounding air within the drive chamber act as resistance forces upon the platters. These resistance forces are called "tribological" forces and are related to the surface rubbing of the surrounding air of the drive chamber and the spinning platters. At 3600 RPM, conventional disk drives require approximately 1 to 2 watts of power in order to maintain this rate and overcome the tribological forces acting upon the platters within the drive chamber.
A percentage of the power input to the disk drive platters is expended as heat throughout the surface of drive units. Therefore, as more power is required to maintain high spin rates, the drive unit begins to heat up and radiate a large amount of unwanted heat. Since hard disk drives are often situated in computer systems in close proximity with electrical boards, it is not desirable that disk drives radiate heat. Excessive radiated heat causes electric circuits, chips and components to malfunction. It would be advantageous to be able to reduce the amount of tribological forces upon disk drives in order to reduce the power required to maintain high platter spin rates. This would be advantageous because the heat radiated by disk drives could then be reduced. The present invention offers a solution to this problem by reducing the tribological forces on drive mechanisms.
Another reason to reduce the power consumption of disk drives is for power conservation. An increasing number of laptops and battery operated computers are becoming available and popular. These computers have only a limited amount of energy to power all of their components. The continuous spinning of the drive platters consumes a large percentage of the battery lifetime. If power consumption could be reduced at increased spin rates, then battery powered computer systems could operate at longer durations in between battery charges.
The present invention solves the above problems by providing an apparatus and method to increase the platter spin rate in disk drives while reducing the overall power consumption and heat radiation of the disk drive.
Also, the disk drive chambers of prior art disk drives are sealed with air located within the chamber. Since air contains a mixture of nitrogen and oxygen (among other elements), a large amount of oxygen is trapped within the drive chamber and exposed to the surfaces of the drive platters. Through a well known process, oxidation occurs on the metallic drive platters which can destroy the data bearing surfaces of the platters by marking the platters or "pitting" the platter surfaces which must remain smooth because the read/write heads fly so close to the platter surface. It would be advantageous to eliminate this oxidation problem to increase the life span of hard disk drives and decrease failure rates. The present invention also offers such a solution.
Within hard disk drives, information is transferred to and from the drive platters through the magnetic read/write heads by way of flexcircuits which couple to the drive heads. Special flexible flexcircuits also couple the actuator arm in order to control the movement of this arm and the associated magnetic read/write heads. These flexcircuits must be able to couple to the read/write heads, the actuator arm movement device, and to the platter spin motor which are all situated inside the sealed chamber. The other ends of these flexcircuits must be able to connect to the outside of the sealed chamber to a disk drive controller circuit on a PC board. A typical prior art disk drive 110 is shown in FIG. 1. A base 101 is shown which provides a mounting surface for the actuator arm and the platters and other drive mechanisms. Case 100 is placed over the base 101, the platters (not shown), and the actuator arm (not shown) in order to provide the sealed chamber. As can been seen, flexcircuits and connectors 103 and 102 are shown extending from the junction of the sealed chamber. The free ends of the connectors are exposed outside the sealed chamber and the other ends are coupled within the chamber to the actuator arm movement, the read/write heads, and the platter spin motor (actuator). The cables 102 and 103 are standard flexible connectors and will hook inside under base 101 in order to connect to receiving connectors of a PC board located and mounted under base 101 which acts as a hardware controller device.
It can be seen that the flexcircuits 102 and 103 are placed through the junction of the base 101 and the case 100. In order to maintain the sealed chamber with these flexcircuits present in this junction, the junction of the case 100 and the base 101 must be epoxy or glue sealed. The epoxy flows around the irregularly shaped cables to insure a proper chamber. However, once the base 101 and the case 100 are sealed by epoxy, glue, or cement, they are permanently affixed together. This makes repair of the components located within the chamber almost impossible since the chamber junction must be cut in order to access these components throwing dust and debris into the chamber. Also, these flexcircuits extend outward from the disk drive unit. They often tear and rip if caught during manufacturing on an assembly line; this sometimes destroys the entire drive unit. Because of the length of the flexcircuit they also produce unwanted stray capacitance in the disk drive system that increases as data access frequency increases. For these reasons, it would be advantageous to eliminate the flexcircuits from the junction of the base 101 and the case 100 to allow the case 100 and base 101 to be connected "flush." The present invention allows for such a function. The present invention provides a method and means where the disk drive case and base can be coupled together without a permanent sealer because the flexcircuits are not located within the base and case junction of the sealed chamber.
Therefore, it is an object of the present invention to provide a hermetically sealed chamber within a disk drive capable of holding gas at a pressure above that of ambient pressure and capable of being manufactured practically. It is an object of the present invention to provide a special connector mechanism and manufacturing process which eliminates flexcircuits between the junction of the hermetically sealed chamber.
Also, it is an object of the present invention to provide a method and means to increase drive platter rotation rate at lower energy levels. It is also an object of the present invention to reduce oxidation of the platters. It is yet another object of the present invention to provide a method and means for easy access to the components within the sealed chamber for repair by specially locating the connector devices which couple the components within the sealed chamber to a hardware controller. These objects, as well as others not specifically mentioned, will become clear by the discussions and descriptions which follow.